Preparation Technology of Wood‐Fiber‐Based Electrothermal Element via Polymeric Diisocyanate for Processing Optimization and Electrothermal Performance

ABSTRACT A novel wood‐fiber‐based electrothermal element (WFEE) was prepared using polymeric 4,4′‐diphenylmethane diisocyanate and multiwalled carbon nanotubes/graphene oxide via hot pressing. An orthogonal experimental design was employed to determine the optimal hot‐pressing parameters for the developed WFEE. The maximum values of bending strength (BS), bending modulus (BM), internal bond strength (IB), and 24‐h thickness swelling (24‐h TS) were 51.30 MPa, 8.52 × 10 3 MPa, 1.27 MPa, and 14.68%, respectively. Range and variance analyses indicated that the optimal process parameters were a pressure of 4 MPa, temperature of 170°C, time of 2 min, and adhesive content of 12 wt%. Under these conditions, the WFEE showed improvements in BS, BM, IB, and 24‐h TS by 39.88%, 3.03%, 29.56%, and 4.01%, respectively. Furthermore, the stable temperature reached 196.77°C at 20 V, and the WFEE exhibited good electrothermal stability after multiple thermal cycles under continuous applied voltage. Overall, the results demonstrate that the developed WFEE possesses high mechanical and electrothermal properties, and provide technical parameters for the preparation of new electrothermal element.